Can I use water from my arowana tank to start marine tank?

[Patrick]

Hi, I am converting my arowana tank to marine. Instead of cycling water from scratch, I am thinking of using water from my arowana tank to start a marine tank i.e. change 30% of water and put marine salt and let it run for a few days. I intend to keep marine fishes only. Will the existing bacteria in the cannister filter die due to high salinity? Is it a good idea? All advice are welcome. Thanks!

[miketeo3]

Not only bacteria in your canister as consideration. Your arowana water source from where? Tap water? You will contribute phosphate and silicate when converting to marine tank. i don't think it is a good start. it is different world.

[Patrick]

Not only bacteria in your canister as consideration. Your arowana water source from where? Tap water? You will contribute phosphate and silicate when converting to marine tank. i don't think it is a good start. it is different world.

Thanks for your advice bro Mike Looks like I have to clean up the tank and cannister thoroughly ya...

[angelfishlover]

Then Arowana poop a lot=nitrates and phosphates.So i suggest you use DI water.And restart since the bacteria will suffer salinity shock.

[Firestarter]

No, please do not use the water from your FW tank. I suggest that you restart the tank from scratch. What is the size of your tank? Thickness of the glass? Do note that FW tanks are not recommended for marine use because the thickness of the glass is thinner. This will depend on the size of your tank.

Also, it is not true that you cannot start a marine tank using tap water. Just that tap water contains phosphates and nitrates which will lead to algae blooms and not so good in the long run.

[Patrick]

Thanks bros for your advice.

[andyboss]

one question: how come marine tank requires thicker glass compare to FW tankl?

No, please do not use the water from your FW tank. I suggest that you restart the tank from scratch. What is the size of your tank? Thickness of the glass? Do note that FW tanks are not recommended for marine use because the thickness of the glass is thinner. This will depend on the size of your tank.

Also, it is not true that you cannot start a marine tank using tap water. Just that tap water contains phosphates and nitrates which will lead to algae blooms and not so good in the long run.

[limsc]

one question: how come marine tank requires thicker glass compare to FW tankl?

Reason is bcos marine uses salt water(Specific Gravity=1.025) and it is denser than fresh water(SG=1).

So for the same volume, the contents is much heavier.

[Firestarter]

He is right. Marine tanks have more specific gravity than FW tanks.

Just imagine a layman comparison,

Example:

3ft 100G FW tank

Total weight of water = 300L = 300kg

3ft 100G Marine tank

Total weight of water = 300L = 300kg

Salt required = 20kg

Live Rocks = 50kg

Total weight (content) of FW tank = 300kg

Total weight (content) of Marine tank = 470kg

That is why you need a thicker glass tank for marine setups. The bigger the tank, the thicker the glass.

Patrick, your tank how many ft?

How many mm is your glass thickness?

[Patrick]

He is right. Marine tanks have more specific gravity than FW tanks.

Just imagine a layman comparison,

Example:

3ft 100G FW tank

Total weight of water = 300L = 300kg

3ft 100G Marine tank

Total weight of water = 300L = 300kg

Salt required = 20kg

Live Rocks = 50kg

Total weight (content) of FW tank = 300kg

Total weight (content) of Marine tank = 470kg

That is why you need a thicker glass tank for marine setups. The bigger the tank, the thicker the glass.

Patrick, your tank how many ft?

How many mm is your glass thickness?

- I didnt ask the LFS shop thickness because at that time I just wanted a tank for FW. Bought a half round 2.5ft tank. Will drop by the shop and ask them later. Thanks bros you all are very and very helpful.